Global fossil fuel emissions are projected to fall by 0.4 percent in 2026, marking the first annual decrease since the 2020 Covid pandemic. According to the Global Carbon Budget report, this decline is being driven by the expansion of renewable energy and an oil price shock linked to the war in Iran.
The research, published in the journal Earth System Science Data as nations gather for the COP31 climate summit in Antalya, Turkey, highlights a shift from a decade of growth. Emissions from burning oil, gas, and coal rose by an average of 0.9 percent per year over the last ten years, reaching a record high in 2025.
Specific factors contributed to the 2026 projection. The US-led war in Iran and the closure of the Strait of Hormuz caused crude prices to soar, leading to a drop in oil consumption. Additionally, the deployment of wind farms, solar panels, and electric vehicles played a role, with the report finding that two thirds of the increase in global energy demand is now met by these technologies.
However, experts warn that this reduction may be temporary. Pierre Friedlingstein, director of the Global Carbon Budget Office at the University of Exeter in Britain, stated that while a decline in fossil CO2 emissions is encouraging, a reduction driven partly by geopolitical shocks is not a sustainable climate solution. He noted that the long-term answer remains the rapid deployment of clean energy technologies.
Corinne Le Quere, a climate change science professor at the University of East Anglia, suggested a rebound is likely "when the oil tensions go away," noting that emissions typically rebound when economies recover from shocks like Covid or the global financial crisis. The researchers noted that while oil-related emissions dropped 1.9 percent last year, it was "likely a short-term response to the energy shock triggered by the Iran conflict."
The report provides a mixed outlook for different fuels and land use. Gas emissions are set to fall by 0.3 percent, but coal use emissions are expected to rise by 0.6 percent. Total CO2 emissions, which include land-use changes like deforestation, are projected to rise to 43.3 billion tonnes in 2026 from 42.8 billion tonnes last year. Researchers attribute the rise in land-use emissions partly to peat fires and forest degradation in southeast Asia caused by drier conditions from this year's strong El Nino pattern.
The world's carbon budget—the amount of CO2 that can be emitted before global warming exceeds 1.5C above pre-industrial levels—stands at 150 billion tonnes. Researchers calculated that at current rates, this budget will be exhausted in less than four years. While nations agreed in 2015 to pursue a 1.5C limit, the United Nations declared in September that this long-term target would be missed in a matter of years. Scientists emphasize that reducing fossil fuel emissions is crucial to limiting the period of "overshoot" above 1.5C and bringing temperatures down quickly.
